Bilateral popliteal artery aneurysms in a young man with Loeys-Dietz syndrome

Open Surgical Repair in a Patient With Loeys-Dietz Syndrome and Extensive Vascular Compromise: A Case Report and Literature Review

Loeys-Dietz syndrome (LDS) has been associated with multiple vascular abnormalities involving the entire arterial tree. However, limited reports regarding compromise in the aortoiliac and femoral bifurcation are available. Further, recommendations for optimal approach, thresholds for diameter at the time of surgery, and surveillance are also limited. We present a case of a 67-year-old male patient with LDS and aneurysmal aortoiliac and enlarging common femoral arteries aneurysms, who underwent open surgical repair. His past surgical history included multiple vascular interventions for lower extremity claudication and bilateral hip replacements. The right hip arthroplasty was previously removed due to infection. From the vascular standpoint, the patient underwent staged endovascular left hypogastric artery embolization and open aorto-bi-profunda bypass with a Rifampin-soaked Dacron graft. At 5-month follow-up, he remains asymptomatic with healed incisions and patent bypasses. This case highlights the challenges in managing peripheral aneurysms in LDS patients, emphasizing the need for tailored treatment strategies. While open repair is preferred, endovascular options may be considered in selected cases. Surveillance remains critical with annual cross-sectional imaging. Surgical planning is intricate due to comorbidities, anatomical complexities, and previous surgical infection. Surveillance of these patients must be strict as multiple vascular and non-vascular complications may arise. Therefore, collaborative decision-making is essential for optimal outcomes in this known high-risk population with connective tissue disorders.

Apolipoprotein E (ApoE) Rescues the Contractile Smooth Muscle Cell Phenotype in Popliteal Artery Aneurysm Disease

Popliteal artery aneurysm (PAA) is the most frequent peripheral aneurysm, primarily seen in male smokers with a prevalence below 1%. This exploratory study aims to shed light on cellular mechanisms involved in PAA progression. Sixteen human PAA and eight non-aneurysmatic popliteal artery samples, partially from the same patients, were analyzed by immunohistochemistry, fluorescence imaging, Affymetrix mRNA expression profiling, qPCR and OLink proteomics, and compared to atherosclerotic (n = 6) and abdominal aortic aneurysm (AAA) tissue (n = 19). Additionally, primary cell culture of PAA-derived vascular smooth muscle cells (VSMC) was established for modulation and growth analysis. Compared to non-aneurysmatic popliteal arteries, VSMCs lose the contractile phenotype and the cell proliferation rate increases significantly in PAA. Array analysis identified APOE higher expressed in PAA samples, co-localizing with VSMCs. APOE stimulation of primary human PAA VSMCs significantly reduced cell proliferation. Accordingly, contractile VSMC markers were significantly upregulated. A single case of osseous mechanically induced PAA with a non-diseased VSMC profile emphasizes these findings. Carefully concluded, PAA pathogenesis shows similar features to AAA, yet the mechanisms involved might differ. APOE is specifically higher expressed in PAA tissue and could be involved in VSMC phenotype rescue.

Iliac branch endoprosthesis for repair of a common iliac artery aneurysm in Loeys-Dietz syndrome type 3

The commercial availability of the iliac branch endoprosthesis (IBE) has permitted endovascular repair of iliac artery aneurysms with the preservation of pelvic circulation. However, the device instructions for use require certain anatomic criteria that can limit deployment in ≤30% of patients. Moreover, branched endovascular treatment of common iliac artery aneurysms with IBE in patients with connective tissue disorders such as Loeys-Dietz syndrome has not been described. In the present report, we have described our technique of alternative endograft aortoiliac reconstruction to overcome anatomic barriers to IBE placement in a patient with a giant common iliac artery aneurysm in the setting of a rare pathogenic variant in the SMAD3 gene.

Ecto-5'-nucleotidase (Nt5e/CD73)-mediated adenosine signaling attenuates TGFβ-2 induced elastin and cellular contraction

Arterial calcification due to deficiency of CD73 (ACDC) is a rare genetic disease caused by a loss-of-function mutation in the NT5E gene encoding the ecto-5'-nucleotidase (cluster of differentiation 73, CD73) enzyme. Patients with ACDC develop vessel arteriomegaly, tortuosity, and vascular calcification in their lower extremity arteries. Histological analysis shows that patients with ACDC vessels exhibit fragmented elastin fibers similar to that seen in aneurysmal-like pathologies. It is known that alterations in transforming growth factor β (TGFβ) pathway signaling contribute to this elastin phenotype in several connective tissue diseases, as TGFβ regulates extracellular matrix (ECM) remodeling. Our study investigates whether CD73-derived adenosine modifies TGFβ signaling in vascular smooth muscle cells (SMCs). We show that Nt5e-/- SMCs have elevated contractile markers and elastin gene expression compared with Nt5e+/+ SMCs. Ecto-5'-nucleotidase (Nt5e)-deficient SMCs exhibit increased TGFβ-2 and activation of small mothers against decapentaplegic (SMAD) signaling, elevated elastin transcript and protein, and potentiate SMC contraction. These effects were diminished when the A2b adenosine receptor was activated. Our results identify a novel link between adenosine and TGFβ signaling, where adenosine signaling via the A2b adenosine receptor attenuates TGFβ signaling to regulate SMC homeostasis. We discuss how disruption in adenosine signaling is implicated in ACDC vessel tortuosity and could potentially contribute to other aneurysmal pathogenesis.

Multiple deep femoral artery aneurysms with Loeys-Dietz syndrome

A 60-year-old man with Loeys-Dietz syndrome (LDS) underwent surgery for multiple left deep femoral artery aneurysms (DFAAs). An intraoperative graft replacement was performed from the common femoral artery to the distal DFAAs; the superficial femoral artery was sutured to the graft. DFAAs in association with LDS and the occurrence of multiple DFAAs are rare. To the best of our knowledge, no studies have reported their coexistence. Graft replacement was decided as the optimal treatment for our patient. However, treatment should be considered on a patient-by-patient basis. Therefore, a lower limb arterial examination should accompany the screening of patients with LDS.

Endovascular repair of tortuous recurrent femoral-popliteal aneurysm in a patient with Loeys-Dietz syndrome

Loeys-Dietz syndrome is a rare connective tissue disorder with widespread arterial tortuosity and aneurysms. This syndrome is most notable for its aortic disease, including aortic root dilation and aortic dissection or rupture. Although not as well studied, peripheral artery aneurysms are a prevalent concurrent manifestation and have previously been repaired with both open and endovascular approaches. There are minimal data about the durability and technical considerations of endovascular repair in this disease. We report a case of a patient who developed an extremely tortuous recurrent femoral-popliteal artery aneurysm secondary to aneurysmal degeneration around previously placed stents that was treated with an endovascular approach.

Surgical Management of Peripheral Vascular Manifestations of Loeys-Dietz Syndrome

BACKGROUND

Loeys-Dietz syndrome (LDS) is characterized by a triad of aortic aneurysm, vessel tortuosity, and hypertelorism. LDS patients often harbor additional aneurysms and dissections throughout their vasculature. The optimal management of these additional lesions is poorly understood. Accordingly, we sought to analyze our experience with the peripheral arterial manifestations of LDS.

METHODS

Adult and pediatric LDS patients who sought treatment at a single institution from 2005 to 2015 were retrospectively reviewed. Patients were included if radiographic or clinically documented evidence existed of peripheral artery aneurysm or dissection. Standard univariate analyses were performed.

RESULTS

Eighteen LDS patients (aged 1.3-59.3 years, mean age 27.8 years at diagnosis) with aortic (not including root, ascending, or arch) vascular abnormalities were identified. Average follow-up was 5.2 ± 3.8 years. Fourteen (77.8%) patients had peripheral aneurysms, occurring most frequently in the carotid (35.7%), subclavian (35.7%), and visceral (28.6%) segments. Most patients had multiple peripheral segments involved (average 2, range 1-6). Nine (64%) patients with peripheral involvement underwent repair, for a total of 17 operations (average 1.89 operations per patient, range 1-4). Endovascular techniques were used in 4 operations (23.5%), without technical failures. Among patients requiring surgical repair, a history of abdominal aortic repairs was present in 77.8%, yielding a total of 36 vascular repairs (average 4, range 2-7). Perioperative morbidity was 11.8%, with no reported mortalities. Prior aortic dissection was not associated with peripheral surgical repairs (P = 0.58).

CONCLUSIONS

LDS is an aggressive vasculopathy which commonly affects the peripheral vasculature. Our data suggest that open and endovascular procedures may be safe and effective in the LDS periphery and multiple operations are common. As prior aortic dissection did not predict peripheral arterial involvement in LDS, vigilant peripheral arterial surveillance of LDS is warranted regardless of aortic disease state and may be key to early identification and our treatment success.

Late Peripheral Thoracic Aneurysms following Aortic Root Surgery in Patients with Loeys-Dietz Syndrome

The Loeys-Dietz syndrome is a multisystem connective tissue disorder characterized by aortopathy, arterial tortuosity, peripheral aneurysms, and skeletal features. The peripheral arteriopathy is an important cause of morbidity and potential mortality. This report presents 2 cases: the first demonstrating a 5-cm pseudoaneurysm of the right internal mammary artery and the second demonstrating a 2.3-cm aneurysm of the left internal mammary artery, each following aortic root surgery. These were successfully treated with percutaneous techniques. No complications were seen at follow-up as long as 2 years. Patients with Loeys-Dietzs syndrome require comprehensive long-term vascular follow-up and are likely to require percutaneous vascular interventions.

Giant vein graft aneurysm complicated by Loeys-Dietz syndrome

Loeys-Dietz syndrome (LDS) is a recently reported autosomal dominant aortic aneurysm syndrome with widespread systemic involvement. Although connective tissue diseases carry a theoretical risk of aneurysmal degeneration in vein grafts, there are no reports of vein graft aneurysm (VGA) in patients with connective tissue disease. We herein report the first case of a giant VGA that was manifested 5 years after the reconstruction of a popliteal artery aneurysm associated with LDS. A pathologic examination of the VGA revealed high proteoglycan deposition and medial degeneration of the diffuse type in the VGA; these findings conformed to LDS.

Acute dilatation of the ascending aorta and aortic valve regurgitation in Loeys-Dietz syndrome

Loeys-Dietz syndrome (LDS) is a recently recognized connective tissue disorder caused by mutations of the transforming growth factor (TGF)-β receptors. It is an autosomal dominant syndrome characterized by the triad of arterial tortuosity and aneurysms, hypertelorism, and bifid uvula or cleft palate. We treated an 18-year-old woman with a 100-mm-diameter aortic root aneurysm and severe aortic valve regurgitation. She underwent urgent aortic root replacement and bioprosthetic valve implantation. LDS was diagnosed by postoperative genetic screening results. Histopathologic examination of the aortic wall showed diffuse degeneration and elastin fragmentation in the media.

Loeys-Dietz syndrome: a primer for diagnosis and management

Loeys-Dietz syndrome is a connective tissue disorder predisposing individuals to aortic and arterial aneurysms. Presenting with a wide spectrum of multisystem involvement, medical management for some individuals is complex. This review of literature and expert opinion aims to provide medical guidelines for care of individuals with Loeys-Dietz syndrome.